Laser Shock Peening of Ti6Al4V Alloy with Combined Nanosecond and Femtosecond Laser Pulses

Abstract

Laser shock peening (LSP) with nanosecond or femtosecond laser pulses is applied to improve the mechanical properties of metallic materials. Thus, it is necessary to compare the effects of different processing methods on microstructure changes and property improvement. In this study, nanosecond LSP (NLSP), femtosecond LSP (FLSP), and LSP with combined nanosecond and femtosecond laser pulses (F-NLSP) are conducted on Ti6Al4V alloys to compare the surface morphologies, in-depth microstructures, and nanohardness changes. In FLSP, the peened surface is smooth, and the affected depth is limited near the peened surface. NLSPed and F-NLSPed samples present rough surfaces due to the severe ablation process. Small equiaxed grains with no preferred grain orientation are denser in F-NLSPed samples than that in NLSPed samples. Compared with NLSPed samples, the affected depth and amplitude of in-depth nanohardness are larger in F-NLSPed samples. This is attributed to the increased laser absorption of incident laser on the treated surface by femtosecond laser pulses. The results in this study show the effects of different LSP methods and provide chances in engineering potentials for material property improvements.

Study on the Effects of Multiple Laser Shock Peening Treatments on the Electrochemical Corrosion Performance of Welded 316L Stainless Steel Joints

“…In the process of increasing the number of shocks, part of the energy is absorbed by the black tape, and the other part serves as the driving force for the annihilation and resetting of high-density dislocations inside the material. As a result, the dislocation entanglement transforms to form new grain boundaries, and the original coarse grains are divided by the new grain boundaries to form fine grains, which is called grain refinement [25][26][27][28].…”

Micromorphology, Microstructure, and Wear Behavior of AISI 1045 Steels Irregular Texture Fabricated by Ultrasonic Strengthening Grinding Process

“…Therefore, it is necessary to enhance the antiwear properties of the contact surfaces to prevent them from experiencing dry frictional wear. Many solutions have been proposed to address this issue, such as surface alloying [4], surface coating [5,6], surface texturing [7,8], and surface nanocrystallization [9,10]. Surface texturing has emerged as a promising solution in recent decades [11][12][13][14].…”